This package has Build-Depends on GTK 2 (libgtk2.0-dev), or produces
binary packages with a Depends on GTK 2.

GTK 2 was superseded by GTK 3 in 2011 (see
<https://bugs.debian.org/947713>). It no longer receives any significant
upstream maintenance, and in particular does not get feature development
for new features like UI scaling on high-pixel-density displays (HiDPI)
and native Wayland support. GTK 3 is in maintenance mode and GTK 4 is
approaching release, so it seems like a good time to be thinking about
minimizing the amount of GTK 2 in the archive.

GTK 2 is used by some important productivity applications like GIMP, and
has also historically been a popular UI toolkit for proprietary software
that we can't change, so perhaps removing GTK 2 from Debian will never be
feasible. However, it has reached the point where a dependency on it is
a bug - not a release-critical bug, and not a bug that can necessarily
be fixed quickly, but a piece of technical debt that maintainers should
be aware of.

A porting guide is provided in the GTK 3 documentation:
https://developer.gnome.org/gtk3/stable/migrating.html

Some libraries (for example libgtkspell0) expose GTK as part of their
API/ABI, in which case removing the deprecated dependency requires
breaking API/ABI. For these libraries, in many cases there will already
be a corresponding GTK 3 version (for example libgtkspell3-3-0), in which
case the GTK 2-based library should probably be deprecated or removed
itself. If there is no GTK 3 equivalent, of a GTK 2-based library,
maintainers should talk to the dependent library's upstream developers
about whether the dependent library should break API/ABI and switch
to GTK 3, or whether the dependent library should itself be deprecated
or removed.

A few packages extend GTK 2 by providing plugins (theme engines, input
methods, etc.) or themes, for example ibus and mate-themes. If these
packages deliberately support GTK 2 even though it is deprecated, and
they also support GTK 3, then it is appropriate to mark this mass-filed
bug as wontfix for now. I have tried to exclude these packages from
the mass-bug-filing, but I probably missed some of them.

Regards,
    smcv

This depends on upgrading Castle Game Engine class (TCastleWindowBase) to
GTK3. See my comments in
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=967284 -- we will do it :)

Once the upgrade to GTK3 in Castle Game Engine is done, then view3dscene
will just be able to use it, without any additional work.

Regards,
Michalis

Meanwhile, you can drop libgtkglext1-dev, which is not used, and unblock #967491.

Pushed to Salsa, 4.2.0-3
https://salsa.debian.org/pascal-team/view3dscene

Control: reassign -1 castle-model-viewer

* Abou Al Montacir <abou.almontacir@sfr.fr>, 2025-01-07 08:58:

There's no such package in Debian.

I see it is in NEW. Can we please stop adding more GTK2 packages?

Hi Jakub, Bastian,

F.Y.I  Upstream have renamed view3dscene as castle-model-viewer.
      That is why the bug was reassigned.

So while castle-model-viewer is in NEW, is is not actually new.
Its a new version of view3dscene with a new name.


Regards,
Peter B

As announced [1], we are trying to remove gtk2 from forky. Therefore,
I am raising the severity of this issue.

[1] https://lists.debian.org/debian-devel/2026/01/msg00090.html

On behalf of the Debian GNOME team,
Jeremy Bícha

Do we have a fix for this? It seems we need to either re-write or drop
ClassicLadder.

( I'm upstream of Castle Game Engine and Castle Model Viewer. )

This should be solved once we release new Castle Game Engine, and it will be packaged in Debian along with new Castle Model Viewer.

The latest Castle Game Engine has `TCastleWindow` backend using GTK 3 by default (not GTK 2). `TCastleWindow` is a class used to initialize window in Castle Model Viewer and most CGE examples. So, simply recompiling the application using the latest Castle Game Engine will fix this issue for Castle Model Viewer.

See https://castle-engine.io/wp/2026/02/09/upgrade-to-gtk-3/ .
We plan soon (February 2026) to do new releases of Castle Game Engine and Castle Model Viewer.

Regards,
Michalis